RDV91 (Astrometric/Geodetic VLBA-91) 2012 FEB 08 18:00 DOY 039 Notes prepared by David Gordon, Ed Himwich and John Gipson NVI/GSFC Special notes for this experiment ================================= This session will use 2-bit sampling again, as in the last few RDV's. Frequencies and channel bandwidths (8 MHz) are the same as in previous RDV's. The bit rate will be 256 Mbits/sec. The 8 MHz, 2-bit sampling is preferable to 16 MHz, 1-bit sampling because the 16 MHz filters are not very good at the non-VLBA stations. The data will be correlated at the VLBA using the DiFX software correlator. There are 5 non-VLBA stations scheduled (FORTLEZA, MEDICINA, NYALES20, TSUKUB32, and WETTZELL). These stations should see the "Special operations notes for non-VLBA stations" section below for special instructions. To facilitate fringe-finding, there are several long scans on fairly strong sources at most or all of the stations at the beginning of the schedule and near the end. All stations please try to be onsource and recording data for the first of these scans. There are also 3 full-network scans in the middle of the session. These scans are: Source Start DURATIONS (seconds) name yyddd-hhmmss Br Fd Ft Hn Kp La Mc Mk Nl Ny Ov Pt Sc Ts Wz 1954+513 12039-180000| 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300| 3C371 12039-180605| 300 300 300 300 300 300 300 300 300 300 300 300 300 300| 0529+483 12040-032314| 220 220 220 220 220 220 220 220 220 220 220 220 220 220 220| 3C371 12040-102727| 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150| 2229+695 12040-155334| 142 116 382 105 151 114 382 205 108 216 149 114 97 117 180| 1954+513 12040-174617| 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300| 3C371 12040-175223| 200 200 200 200 200 200 200 200 200 200 200 200 200 200| Additional Notes: - Two-bit sampling is used. - In this RDV, all stations will record on Mark5A/B, except Tsukuba. Tsukuba will record on K5 and the data will be later transferred to Mark5A at Haystack Observatory. - The synch time for the VLBA DiFX correlator using Mark5 is only a few seconds. Because of this, the 'early' start has been reduced to 10 seconds. - The fluxes use our most recent models. Purpose ======= This is the first of six coordinated astrometric/geodetic sessions in 2012 that use the full 10-station VLBA plus up to 10 geodetic stations capable of recording VLBA modes. This year's series is a continuation of the highly successful RDV series begun in 1997. These experiments are being coordinated by the geodetic VLBI programs of three agencies: USNO, NASA, and NRAO. The experiments have been designed so that the same data set may be used by each agency for its particular goals. USNO and Bordeaux Observatory will perform imaging and correction for source structure. These sources will establish a set of core reference sources with known structure and precisely known positions. These data will provide the basis for evaluating the long term stability of the radio reference frame and the ultimate accuracy of wide angle astrometric measurements of extragalactic radio sources using VLBI. NASA will analyze this data to determine a high accuracy terrestrial reference frame. The data will incorporate the VLBA stations into the VLBI reference frame through the inclusion of other geodetic stations for which we have long histories. The data will also produce the most accurate Earth rotation results ever produced. We will use these data to make accurate absolute measurements of UT1. NRAO will use these sessions to provide a service to users who require high quality positions for a small number of sources. While the quality of these results will be high, the observing and data reduction overhead required will be minimal because a small number of such sources can be incorporated into a session of the regular geodetic observations, instead of requiring special observations. Sources for this series of experiments will be selected using the proposed approach. For each experiment we will select a set of 70-80 sources from the pool of geodetic, astrometric, and monitoring sources. About 40-50 of these will remain the same from experiment to experiment and will be chosen to optimize the goals of the three groups. A small number of poorly observed and/or new requested sources may also be included to obtain or improve their positions. Schedule information ==================== This is a new schedule generated by David Gordon at GSFC using sked. Schedule file name: rdv91.skd On ftp.aoc.nrao.edu (aspen): VLBA Pointing files: rdv91crd.br rdv91crd.fd rdv91crd.hn rdv91crd.kp rdv91crd.la rdv91crd.mk rdv91crd.nl rdv91crd.ov rdv91crd.pt rdv91crd.sc Summary file: rdv91.sksum Sked file: rdv91.skd Text file: rdv91.txt Vex file: rdv91.vex At IVS Data Center (ftp://cddisa.gsfc.nasa.gov/vlbi/ivsdata/aux/2012/rdv91) Sked file: rdv91.skd Text file: rdv91.txt This experiment uses the 10 VLBA stations and 5 IVS stations. The IVS stations are: FORTLEZA, MEDICINA, NYALES20, TSUKUB32, and WETTZELL. Below is the sked summary: Key: Br=BR-VLBA Fd=FD-VLBA Ft=FORTLEZA Hn=HN-VLBA Kp=KP-VLBA La=LA-VLBA Mc=MEDICINA Mk=MK-VLBA Nl=NL-VLBA Ny=NYALES20 Ov=OV-VLBA Pt=PIETOWN Sc=SC-VLBA Ts=TSUKUB32 Wz=WETTZELL Br Fd Ft Hn Kp La Mc Mk Nl Ny Ov Pt Sc Ts Wz Avg % obs. time: 49 49 49 47 50 50 46 48 49 42 49 50 45 32 36 46 % cal. time: 4 4 3 4 4 4 4 4 4 4 4 4 4 4 4 4 % slew time: 25 23 37 24 23 24 34 23 24 19 23 24 22 15 10 24 % idle time: 21 23 11 25 22 22 15 24 23 35 23 22 28 48 49 27 total # scans: 307 317 252 310 320 317 313 303 311 317 309 318 305 323 316 309 # scans/hour : 13 13 11 13 13 13 13 13 13 13 13 13 13 13 13 13 Avg scan (sec): 139 134 166 131 134 136 127 137 136 113 138 135 128 86 98 128 # data tracks: 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16 # Mk5 tracks: 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16 Total GBytes: 1649 1642 1600 1571 1659 1665 1545 1605 1635 1409 1649 1663 1512 1119 1234 1544 Total GB(M5): 1466 1459 1422 1396 1475 1480 1374 1426 1454 1252 1466 1478 1344 994 1097 1372 # OF OBSERVATIONS BY BASELINE | Br Fd Ft Hn Kp La Mc Mk Nl Ny Ov Pt Sc Ts Wz StnTotal ------------------------------------------------------------------------------------- Br| 224 71 213 240 235 51 191 231 105 258 235 160 105 47 2366 Fd| 117 232 288 296 53 171 270 83 249 301 219 71 46 2620 Ft| 108 99 112 142 50 111 64 78 108 171 13 124 1368 Hn| 217 238 87 133 258 116 201 232 223 65 85 2408 Kp| 290 42 189 263 81 277 295 201 82 40 2604 La| 55 169 281 92 251 309 216 76 51 2671 Mc| 19 64 185 34 51 80 96 273 1232 Mk| 157 66 212 172 123 167 21 1840 Nl| 100 239 276 223 71 61 2605 Ny| 85 87 78 185 189 1516 Ov| 257 174 97 31 2443 Pt| 213 75 47 2658 Sc| 46 78 2205 Ts| 105 1254 Wz| 1198 Number of 2-station scans: 237 Number of 3-station scans: 128 Number of 4-station scans: 140 Number of 5-station scans: 36 Number of 6-station scans: 23 Number of 7-station scans: 36 Number of 8-station scans: 43 Number of 9-station scans: 43 Number of 10-station scans: 66 Number of 11-station scans: 65 Number of 12-station scans: 20 Number of 13-station scans: 9 Number of 14-station scans: 8 Number of 15-station scans: 5 Total # of scans, observations: 859 15494 INTENSIVE BREAKS ================ There will be either one or two 1-hr UT1 Intensive sessions during RDV91. The first is the regular IVS INT01, in which WETTZELL participates. Therefore, WETTZELL is not scheduled here from 039-1815 to 039-1945. The other is a possible USNO/NRAO UT1 intensive session using PIETOWN and MK-VLBA. The timing for this is somewhat flexible - sometime between 15:00 and 23:00 UTC. Therefore, we expext that PT and MK may be taken out of RDV91 for an ~1.5-2.0 hr period sometime during that window. We will leave the timing of this break to the discretion of the VLBA operators. From our standpoint, there is no particular period that is better or worse than another, and the loss of these two antennas for a short period should have only a minimal effect. SOURCE SELECTION ================ There are a total of 91 sources scheduled in this session. Among them, 30 sources are from the astrometric monitoring list, 40 are from the geodetic monitoring list, 14 are previously observed sources that have only a few observations or were observed in only one session, and 7 are new sources whose positions were requested by Y. Kovalev. The 7 requested sources are: 0145+420 01 48 44.55 +42 15 18.9 J0148+4215 0201+398 02 04 05.16 +40 05 03.4 J0204+4005 0306-061 03 09 23.29 -05 59 21.1 J0309-0559 0405-015 04 08 18.57 -01 22 36.2 J0408-0122 1325-133 13 27 42.12 -13 36 01.0 J1327-1336 2005+737 20 04 17.21 +73 55 05.7 J2004+7355 2225+247 22 28 01.49 +25 03 04.3 J2228+2503 SCHEDULING ALGORITHMS ===================== This schedule uses the "SRCEVN SQRT" mode of Sked. In the absence of any constraints, Sked will preferentially observe strong sources that have high visibility. This mode attempts to smooth out the number of observations per source. RECORDING MODE and FREQUENCIES ============================== NOTE: THERE ARE SOME CHANGES FROM PREVIOUS EXPERIMENTS FOR 2-BIT SAMPLING. The data will be recorded using the following setup: 8 channels 1:2 fan-out 16 MHz sample rate 2-bit sampling This recording mode is designated 256-8(RDV). There is no correlator speed-up factor. The frequency sequence covers 490 MHz at X-band and 140 MHz at S-band using 4 channels in each band. This span fits in one VLBA receiver passband but it uses both the high and low parts of the geodetic receivers. Because only 8 channels total are available when observing with the VLBA stations, a wider spanned bandwidth is not advisable. The following tables list the setup for the VLBA stations, the geodetic stations with K5 back ends, and the geodetic stations with Mark IV back ends. These are the SAME frequencies used in all the standard RDV sessions. VLBA | TSUKUB32 Chan Sky Tracks LO IF BBC | LO IF BBC # 1 X 8405.99 2, 4, 6, 8 7900 B 505.99| 7680 1 725.99 3 2 X 8475.99 10,12,14,16 7900 B 575.99| 7680 1 795.99 4 3 X 8790.99 18,20,22,24 7900 B 890.99| 8080 3 710.99 5 4 X 8895.99 26,28,30,32 7900 B 995.99| 8080 3 815.99 6 5 S 2232.99 3, 5, 7, 9 2900 A 667.01| 1600 2 632.99 9 6 S 2262.99 11,13,15,17 2900 A 637.01| 1600 2 662.99 10 7 S 2352.99 19,21,23,25 2900 A 547.01| 1600 2 752.99 13 8 S 2372.99 27,29,31,33 2900 A 527.01| 1600 2 772.99 14 FORTLEZA, NYALES20, VLBA | MEDICINA, WETTZELL Chan Sky Tracks LO IF BBC | LO IF VC VC# Patch 1 X 8405.99 2, 4, 6, 8 7900 B 505.99| 8080.0 1 325.99 3 H 2 X 8475.99 10,12,14,16 7900 B 575.99| 8080.0 1 395.99 4 H 3 X 8790.99 18,20,22,24 7900 B 890.99| 8580.1 3 210.89 5 3(H) 4 X 8895.99 26,28,30,32 7900 B 995.99| 8580.1 3 315.89 6 3(H) 5 S 2232.99 3, 5, 7, 9 2900 A 667.01| 2020.0 2 212.99 9 L 6 S 2262.99 11,13,15,17 2900 A 637.01| 2020.0 2 242.99 10 H 7 S 2352.99 19,21,23,25 2900 A 547.01| 2020.0 2 332.99 13 H 8 S 2372.99 27,29,31,33 2900 A 527.01| 2020.0 2 352.99 14 H Special operations for non-VLBA stations: ========================================= FORTLEZA, Medicina, Ny Alesund, and Wettzell: These stations have Mark IV or Mark 5 racks. Please use the procedures generated by DRUDG. VCs 3 & 4 are used at X-band with IF 1. VCs 5 & 6 are used at X-band with IF 3. VCs 9, 10, 13 & 14 are used at S-band with IF B. The IF3 command in the procedure IFDSX assumes that VC3 and VC10 will be patched to High. Please verify that the switches for your IF3 module are wired this way, and if they are not please edit the IF3 command to change the switches. The standard wiring is described in "help=if3". If you have questions about the wiring, please contact Brian Corey at Haystack. Tsukuba32: These stations use K4-2 VCs and a K5 recorder. Please transfer data to Haystack in Mark IV format. Use the procedures generated by DRUDG. Be sure to set your rack type to K4-2, not K4-2/M4, if that change has not already been made. Please note you will need to comment out the incorrect VC commands in the VCSX8 procedure after the comment about these converters being present, but not used. This will be corrected in a future DRUDG release. Please also set the attenuation and detector appropriately in the va=.. and vb=... commands. The tpicd commands in SX8M12A should be benign and do not need to be commented out unless they cause a problem. If you wish to record back-up channels, please add appropriate valo=..., va=... vblo=... and vb=... commands in the VCSX8 procedure. CHECKLIST for non-VLBA stations =============================== Please follow the checklist below to ensure you have done all the necessary steps for this experiment: 1. Make .prc file with DRUDG and check them out, or use the procedures from the last session. Check out parity check procedures. 2. Make the .snp file with DRUDG. 3. Set up your system to monitor the clocks with the "gps-fmout" or "fmout-gps" commands. If you have questions about this, please contact Ed Himwich as soon as possible. 4. Send a "ready" message an hour or so before the experiment to the ivs-ops mail list. Copy analysts@nrao.edu on your ready message. 5. Send a "start" message soon after you have started recording. Copy analysts@nrao.edu on the message. 6. At the end of the experiment, send a "finish" message summarizing how the experiment was conducted. Copy analysts@nrao.edu on your message. 7. Transfer your log files to your normal log file data center. The directories for three possible servers are listed below: ftp cddisin.gsfc.nasa.gov/ivsincoming directory on vlbeer: feb12 directory on aspen: /astronomy/feb12/rdv91 or /home/archive/e2e/archive/operations/VLBA/observe/feb12/rdv91 NOTE: If you don't normally use aspen, you should not put your log file on that server. The VLBA correlator knows where to find your log files. Correlation =========== This experiment will be correlated at the VLBA on the VLBA-DiFX software correlator. Disks should be shipped (except Tsukuba and FORTLEZA) to Socorro as soon after the experiment as is practical. The Tsukuba data should be e-transfered to Haystack in Mark IV format as soon after the experiment as is practical. FORTLEZA's media is shipped to USNO first, then rerouted to Socorro. Socorro address for media shipping: VLBA Array Operations Center National Radio Astronomy Observatory Attn: Juan Cordova 1003 Lopezville Road Socorro, NM 87801 U.S.A. Phone: 575-835-7000 Shipping and VLBA contact information is also given at: https://science.nrao.edu/facilities/vlba/contact/shipping_information. Please use one of the recommended shipping companies (FedEx, UPS, DHL, TNT). The VLBA needs to process the session at their correlator as soon as possible because of limited media. They prefer to have the data within one week of the observation, but in no case later than two weeks after the observation. Therefore, please ship your media to the VLBA the same day the session ends or the next business day (just like the R1/R4 media is shipped). If you know that there is going to be a problem sending your media to the VLBA the same day the session ends or the next business day, please let us (ivscc@ivscc.gsfc.nasa.gov and David.Gordon-1@nasa.gov) know as soon as possible so that we, along with the VLBA, can determine the best course of action. If you have any questions or comments, please let us know.